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1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To)

01-08-2006 Final 05-01-2004 to 10-31-2005

4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER

Strategic Partnership for Research in Nanotechnology

5b. GRANT NUMBER

FA9550-04-1-0331

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) 5d. PROJECT NUMBER

Barbara, Paul F.

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

University of Texas at Austin REPORT NUMBER

Center for Nano and Molocular Science and TechnologyI University StationA5300 Austin, TX 78712

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)

Harold Weinstock, Program Manager, Physics and Electronics Directorate/M/Air Force Office of Scientific Research875 North Randolph Street, Suite 325 11. SPONSOR/MONITOR'S REPORTArlington, VA 22203 NUMBER(S)

12. DISTRIBUTION/AVAILABILITY STATEMENT

DISTRIBUTION A. Approved for public release; distribution unlimited.AFRL-SR-AR-TR-07-0477

13. SUPPLEMENTARY NOTES

14. ABSTRACT

This final report discusses researchers working at The University of Texas at Austin whose work has been possible through theStrategic Partnership in Nanotechnology (SPRING) grant. These researchers have either received support directly from awarded

funds or used equipment purchased through this grant. The research can be broken into two research areas "Nanotechnology for

Energy Needs" and "Nanoelectronics". Highlights of both projects are outlines below. The SPRING award also made a largenumber of instrument purchases possible. Much of this equipment is housed in the SPRING/KECK clean room facility which is an

open facility serving the University of Texas at Austin.

15. SUBJECT TERMS

Single Molecule Spectroscopy, Photovoltaics, Nanoelectronics, Organic Elements

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF RESPONSIBLE PERSONa. REPORT b. ABSTRACT c. THIS PAGE ABSTRACT OF Lackowski, William M.

PAGES

U U U UU 7 19b. TELEPHONE NUMBER (Include area code)(512) 232-3695

Standard Form 298 (Rev. 8/98)Prescribed by ANSI Std. Z39.18

Final Report for "Strategic Partnership for Research in Nanotechnology"May 1, 2004 to October 31, 2005

Grant Number: FA9550-04-1-0331Principal Investigator: Paul BarbaraInstitution: The University of Texas at Austin

This final report covers a number of researchers working at The University of Texas at

Austin whose work has been possible through the Strategic Partnership in

Nanotechnology (SPRING) grant. These researchers have either received support

directly from awarded funds or used equipment purchased through this grant. The

research can be broken into two research areas "Nanotechnology for Energy Needs" and

"Nanoelectronics". Highlights of both projects are outlined below.

1. Nanotechnology for Energy Needs

Developing new methods to meet the world's ever increasing energy demands

will require radical solutions that nanoscience and nanotechnology have the potential to

address. The CNM faculty members are tackling these new problems in two major areas

of renewable energy research photovoltaics and hydrogen fuel cells. The CNM efforts

couple both basic science and engineering to develop new materials, understanding, and

devices.

An excellent example of our approach is the research of Dr. Paul Barbara

(Chemistry and Biochemistry) whose research lab has developed powerful single

molecule spectroscopy tools to characterize individual conjugated polymers. [Barbara,

2005] [Palacios, 2006] We support fundamental research on photovoltaics including work

electrochem studies of organics, single molecule spectroscopy of organic materials in a

device environment, and nanoparticle synthetic research. This method involves

simultaneous single molecule fluorescence spectroscopy while controlling

oxidation/reduction of individual molecules or nanoparticles in an electronic device. The

technique, which is denoted by F-V/SMS (where "F" signifies fluorescence intensity), is

analogous in several ways to current vs. voltage (I- P) measurements for devices and

electrochemical cells. For example, F-V/SMS data at different sweep rates can be

20071108136

analyzed to obtain information on both energetics and kinetics of charge transfer

(oxidation/reduction) processes involving the single molecules. This approach is

particularly useful for studying the interactions between excitons and polarons. This is

achieved by recording the single molecule fluorescence intensity as a function of device

bias, which controls the population of polarons. This method also offers a unique means

for characterizing the chemical nature of the poorly understood photochemically induced

intermediate states of conjugated polymers that are responsible for fluorescence

"blinking" and "flickering", i.e. intermittency. By studying the bias dependence of the

SMS during the lifetime of the fluorescence "flickering" intermediate, information on the

oxidation/reduction properties (e.g HOMO energies) of the intermediate can be

determined. In particular, Park et al have applied the technique to elucidate the chemical

nature of photo-oxidation intermediates causing photo-bleaching of MEH-PPV in an

electronic device structure.

Also working in the area of fundamental photovoltaics is David Vanden Bout's

(Chemistry and Biochemistry) group. They are utilizing high-resolution optical

microscopy techniques that are capable of mapping out fluorescence lifetimes on the

nanoscale to probe charge separation in conjugated poomer thin films. [Bunz, 2005] This

initial charge separation is critical to the success of any photovoltaic device. Also,

crucial to the advancement of photovoltaic research are new materials. In particular,

hybrid photovoltaics comprised of both organics and inorganics rely on high quality

monodisperse nanoparticles. Keith Stevenson's (Chemistry and Biochemistry) group is

working on characterization of charge transport behavior in organic and metal oxide thin

films. This project focuses on the development of high resolution optical

and scanning probe microscopy tools for evaluation of charge transport in heterogeneous,

nanostructured materials. [McEvoy, 20006] Spatially resolved measurements obtained at

nanoscopic length scales aids in the understanding of structure-property and materials

performance

relationships crucial for the development of next-generation batteries, fuel cells, and solar

cells.

Brian Korgel's (Chemical Engineering) research group has developed a number

of synthetic methods for the production of bulk quantities of high quality semiconductor

nanowires with very low dispersion in size. [Lu, 2005] [Smith, 2006] These nanowires

have a number of applications ranging from photovoltaics to low-energy emissive

displays. Finally, low cost, flexible plastic photovoltaics will require new manufacturing

technology coupled with new plastic electronics. Dr. Lynn Loo (Chemical Engineering)

is leading this effort in the CNM with the development of solution processible organic

and polymer conductors and semiconductors for a variety of applications. [Dickey, 2006]

Another area where nanoscience and technology have the potential to make big

impacts in renewable energy is in the development of fuel cell technology. Allen Bard's

(Chemistry and Biochemistry) research group has been working on mixed metal

nanoparticle catalysts for oxygen reduction, a key step in proton exchange membrane fuel

cells. They have developed a rapid screening method for testing electrocatlysis of

nanoparticle arrays utilizing scanning electrochemical microscopy. These efforts have

lead to the discovery of several non-Pt materials with activities on par with standard Pt

catalysts. [Walsh, 2006]

Nanoscale catalysts have shown promising properties for a number of critical

applications related to renewable energy and green chemical synthesis, because of their

high surface to volume ratio and the ability to produce nanoparticles of a wide variety of

sizes and shape. The laboratory of Richard Crooks (Chemistry and Biochemistry) has

developed a new method for the synthesis of monodisperse dendrimer-encapsulated metal

nanoparticles with well-defined stoichiometry. These protected nanoparticles can be

made from nearly any metal, but when made from platinum and palladium serve as

highly selective catalysts. [Wilson, 2006] The group has recently demonstrated the effect

of size and face selectivity for Pd Nanoparticles.

2. Nanoelectronics

A key emerging area in nanotechnology is nanoelectronics. The CNM has

developed a working partnership with the Microelectronics Research Center (MRC) at

the University of Texas' Pickle Campus to jointly push forward the development of

nanoscale electronics. These efforts include both fundamental research on materials as

well as applied engineering and testing of new nanoscale devices.

One area of Nanoelectronics research is "quantum engineering" of metallic and

magnetic structures. Ken Shih (Physics) investigates how quantum confinement of

electronic states impacts the thermodynamic properties of metallic nanostructures and

how such confinement influences the collective bulk electronic properties such as

magnetism and superconductivity. [Jiang, 2004] [Eom, 2006]

Another area of research in the Shih lab is "quantum coherent control" of

photonic properties of semiconductor nanostructures. Exploration of new possibilities to

control the quantum optical properties of such nanostructures and to harness these

quantum optical properties for novel optical device applications is underway in the lab.

These studies are providing the basic fundamental knowledge necessary for fabrication of

a quantum computing device and quantum information technology. [Wang, 2005]

Ray Chen (Electrical and Computer Engineering) recently invented an ultra-

compact silicon-photonic-crystal electro-optic modulator silicon modulator fabricated by

standard lithographic techniques. This photonic crystal slows the speed of light down

sufficiently that the intensity can be modulated by a very small electric current. [Jiang,

2005] This design requires ten times less power consumption normally needed for

silicon modulators. Once these modulators can be combined with semiconductor lasers

on a silicon platform they will significantly increase interconnect speeds and efficiencies.

Li Shi (Mechanical Engineering) is creating nanowires of thermoelectric

materials (materials capable of converting voltage differences into heat and vice versa).

Based on theoretical calculations these nearly one-dimensional structures should have

exceptional thermoelectric properties. After synthesis of a batch of nanowires, individual

nanostructures are placed onto a micron-sized thermal test bed structure that was

developed and fabricated in Shi's laboratory. Once fastened to the MEMS heater with a

small amount of platinum 'glue', the electrical and thermal properties of individual

nanowires can be measured. [Zhou, 2005] [Shi, 2005]

The CNM efforts in nanoelectronics efforts are also branching out from

traditional semiconductors and into emerging areas such as spintronics. Maxim Tsoi's

(Physics) research is focused on this new technological discipline that refers to studying

the role played by an electron spin in solid-state physics. The main focus of his work is in

current driven spin-transfer phenomena. [Beach, 2005] His research group has recently

demonstrated transfer of spin-angular momentum across and interface between

ferromagnetic and anti-ferromagnetic metals. The spin transfer is mediated by an

electrical current and revealed by variation in the exchange bias at the

ferromagnet/antiferromagnet interface. [Wei, 2006] Current-mediated variation of

exchange bias can be used to control the magnetic state of spin-valve devices, e.g., in

magnetic memory applications which create an entirely new class of high-density non

volatile memory.

3. Instrument Purchases

The SPRING at UT-Austin allowed Paul Barbara and co-workers to add several

key components to the SPRING/KECK clean room on campus. The SPRING/KECK

facility is now set up for optical lithography, additive and subtractive growth/etch

facilities, device packaging (critical point drier, wire bonder, and dicing saw) and

characterization (profilometry, spectroscopic ellipsometry, and digital microscopy). In

fall of 2006 the SPRING/KECK facility will move into the brand new state-of-the-art

Nano Science and Technology (NST) building on campus. An entire floor of the NST

building is comprised of a 3500 square foot hard-wall clean room, split into Class 100

and Class 1000 areas. The new clean room has been designed with integral plumbing and

sensing for a variety of toxic etch and growth gasses allowing for acquisition of more

etch and growth tools. We will also add electron-beam lithography to fabricate devices

with critical dimensions approaching 25 nm.

4. ReferencesP. F. Barbara, A. J. Gesquiere, S.-J. Park, Y. J. Lee; "Single-Molecule Spectroscopy ofConjugated Polymers" Acc. Chem. Res. 2005, 38 602-610.

G. S. D. Beach, C. Nistor, C. Knutson, M. Tsoi, and J. L. Erskine; "Dynamics of Field-Driven Domain Wall Propagation in Ferromagnetic Nanowires" Nature Mater. 2005, 4,741-744.

U. H. F. Bunz, J. M. Imhof, R. K. Bly, C. G. Bangcuyo, L. Rozanski, D. A. Vanden Bout;"Photophysics of Poly[p-(2,5-didodecylphenylene)ethynylene] in Thin Films"Macromolecules 2005, 38, 5892-5896.

K. C. Dickey, J. E. Anthony, Y.-L. Loo; "Improving Organic Thin-Film TransistorPerformance Through Solvent Vapor Annealing of Solution-ProcessableTriethylsilylethnyl Anthradithiophene", Adv. Mater. 2006, 18, 1721-1726.

D. Eom, S. Qin, M.-Y. Chou, C.K. Shih "Persistent Superconductivity in Ultra-Thin PbFilms: A Scanning Tunneling Spectroscopy Study" Phys. Rev. Lett. 2006, 96, 027005.

C.-S. Jiang, S.-C. Li, H.-B. Yu, D. Eom, X. -D. Wang, P. Ebert, J.-F. Jia, Q.-K. Xue,C. K. Shih "Building Pb Nano-Mesas with Atomic Layer Precision,", Phys. Rev. Lett.2004, 92, 106104.

Y. Jiang, W. Jiang, L. Gu, X. Chen, R. T. Chen; "80-Micron Interaction Length SiliconPhotonic Crystal Waveguide Modulator" AppL. Phys. Lett. 2005, 87, 221105.

H. Lin, J. Kim, L. Sun, R. M. Crooks; "Replication of DNA Microarrays from Zip CodeMasters" J. Am. Chem. Soc. 2006, 128, 3268-3272.

X. Lu, D. D. Fanfair, K. P. Johnston, B. A. Korgel; "High Yield Solution-Liquid-SolidSynthesis of Germanium Nanowires" J. Am. Chem. Soc. 2005, 127, 15718-15719.

T. M. McEvoy, J. W. Long, K. J. Stevenson; "Nanoscale Conductivity Mapping ofHybrid Nanoarchitectures: Ultrathin Poly(o-Phenylenediamine) on MesoporousManganese Oxide Ambigels," Langmuir, 2006, 22, 4262-4266.

R. E. Palacios, F.-R. F. Fan, A. J. Bard, P. F. Barbara; "Single-MoleculeSpectroelectrochemistry (SMS-EC)" J. Am. Chem. Soc. 2006, 128, 9028-9029.

L. Shi, C. Yu, J. Zhou; "Thermal Characterization and Sensor Applications of OneDimensional Nanostructures Employing Microelectromechanical Systems" J. Phys.Chem. B. 2005, 109, 22102-22111.

D. K. Smith, D. C. Lee, B. A. Korgel; "High Yield Multiwall Carbon Nanotube Synthesisin Supercritical Fluids" Chem. Mater. 2006, 18, 3356-3364.

L. Torsi, A. Dodabalapur; "Organic Thin-Film Transistors as Plastic Analytical Sensors"Anal Chem. 2005, 77, 380A-387A.

D. A. Walsh, J. L. Fernandez, A. J. Bard; "Rapid Screening of Bimetallic Electrocatalystsfor Oxygen Reduction in Acidic Media by Scanning Electrochemical Microscopy" J.Electrochem. Soc. 2006, 153, E99-E103.

Q. Q. Wang, A. Muller, M. T. Cheng, H. J. Zhou, P. Bianucci, C. K. Shih; "CoherentControl of a V-type Three-Level System in a Single Quantum Dot," Phys. Rev. Lett.2005, 95, 187404.

Z. Wei, A. Sharma, A. S. Nunez, P. M. Haney, R. A. Duine, J. Bass, A. H. MacDonald,M. Tsoi; "Spin Transfer in an Antiferromagnet" Los Alamos National Laboratory,Preprint Archive, Condensed Matter (2006), 1-5, arXiv:cond-mat/0606462.

0. M. Wilson, M. R. Knecht, J. C. Garcia-Martinez, R. M. Crooks; "Effect of Pd

Nanoparticle Size on the Catalytic Hydrogenation of Allyl Alcohol" .. Am. Chem. Soc.

2006, 128, 4510-4511.

J. Zhou, C. Jin, J. H. Seol, X. Li, L. Shi; "Thermoelectric Properties of IindividualElectrodeposited Bismuth Telluride Nnanowires" Appl. Phys. Lett. 2005, 87, 133109-1